Key parameters at a glance

A radius of 0.89 Earth radii
A mass of 0.64 Earth masses
Surface gravity around 0.81 g
An orbital period of 1.937 days
Semi-major axis 0.0240 AU
Equilibrium temperature 802 K (529 °C)
Distance from Earth 684.07 light-years
Earth Similarity Index 0.396
Travel time at Voyager 1 speed 12,063,628 years
Almost certainly tidally locked to its host star given the close orbit

1 sibling around Kepler-303

Kepler-303 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-303 b this	Rocky Terrestrial	0.89	0.64	1.937	802	2014
Kepler-303 c	Rocky Terrestrial	1.14	1.55	7.061	521	2014

Kepler-303 b Planet Profile

Physical Specs

Radius

0.89 R⊕

Radius (Jupiter)

0.079 R♃

Mass

0.64 M⊕

Mass (Jupiter)

0.002 M♃

Density

4.99 g/cm³

Surface Gravity

0.81 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.396

HZ Position Inner

Controversial No

Discovery

Year 2014

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#418of 570

top 73.2%

This planet

0.89R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-387 c 0.89 R⊕ Kepler-1560 b 0.89 R⊕ Kepler-353 b 0.89 R⊕

Metric	Earth	Kepler-303 b	Jupiter
Radius (R⊕)	1.00	0.89	11.21
Mass (M⊕)	1.00	0.64	317.83
Density (g/cm³)	5.51	4.99	1.33
Surface Gravity (g)	1.00	0.81	2.53
Insolation (S⊕)	1.00	145.44	0.037

Star Catalogue Identifiers

TIC

TIC 164460208

Gaia DR2

Gaia DR2 2105113765565227648

Gaia DR3

Gaia DR3 2105113765565227648

System

Kepler-303

Percentile among Rocky Terrestrial cohort

Radius 0.890 R⊕ · percentile 25 / cohort 570

Mass 0.640 M⊕ · percentile 21 / cohort 570

Orbital period 1.94 d · percentile 21 / cohort 567

Distance 209.74 pc · percentile 32 / cohort 566

ESI 0.396 · percentile 59 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

1.937 days

Semi-major axis

0.0240 AU

Eccentricity

0.000

Inclination

89.41 °

Year Length

A year here lasts approximately 1.94 Earth days (0.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0240 AU.

Transit Fingerprint

Depth

0.031 %

Duration

1.535 h

Impact parameter b

0.450

Rp / R★

0.017132

Transit midpoint (BJD)

2,454,967.7187

Photometric dip

Transit produces a flux drop of 312 ppm lasting ≈ 1.54 h.

Extended Orbital Architecture

Planet / star radius ratio

0.017132

Semi-major axis / stellar radius

10.175

Impact parameter (b)

0.450

Transit mid-time (BJD)

2,454,967.7187

Angular separation (arcsec)

0.11400

Eq. Temperature

802K

(529 °C)

Insolation (S⊕)

145.44

Earth = 1.00

Earth Similarity (ESI)

0.396

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Rowe et al. 2014

Instrument

Kepler CCD Array

Publication

2014-03

Observation locale

Space

Discovery cohort

Planets confirmed in 2014 at Kepler (12 shown).

Kepler-186 e · Super-Earth Kepler-395 c · Super-Earth Kepler-220 e · Super-Earth Kepler-249 d · Super-Earth Kepler-296 f · Super-Earth Kepler-367 c · Rocky Terrestrial Kepler-296 e · Super-Earth Kepler-155 c · Sub-Neptune Kepler-138 d · Super-Earth Kepler-333 c · Rocky Terrestrial Kepler-331 d · Super-Earth Kepler-267 d · Sub-Neptune

Host System: Kepler-303

Spectral Class

M-type red dwarf

Effective Temperature

3,944 K — cooler than the Sun (5,778 K)

Estimated Age

7.71 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.485 R☉

Stellar Mass

0.575 M☉

Metallicity [Fe/H]

-0.41

Extended Stellar Properties

Surface gravity (log g)

4.768 dex

Stellar density

5.283 g/cm³

Metallicity ratio

[M/H]

Distance

209.74 parsec

Light-years 684.07 ly

V-band magnitude

14.92 mag

Voyager-speed travel 12,063,628 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

4.739 mas

Total Proper Motion

76.827 mas/yr

PM Right Ascension

2.44 mas/yr

PM Declination

-76.79 mas/yr

Galactic Cartesian (pc)

x = 0.164 · y = -0.705 · z = 0.690

Equatorial (J2000)

RA 283.13547° · Dec 43.65670°

Galactic ℓ, b

73.343° · 18.161°

Ecliptic λ, β

293.851° · 66.012°

HTM-20 index

735759892